The ten people being monitored in Michigan for the Ebola virus have been "cooperative" in their twice-daily communications with public officials, the state's top health official said today.

None have symptoms of being infected with Ebola,said Nick Lyon, director of the Michigan Department of Community Health.

Each of the ten had recently traveled to or from one of three West African countries most affected by the deadly virus: Liberia, Sierra Leone, or Guinea. The ten - most U.S. citizens who were returning home, as well as some who are visiting the U.S. - were flagged by the U.S. Centers for Disease Control and Prevention for "self-monitoring" during the virus' 21-day incubation period after they entered the U.S. One of the ten went to a hospital only as a precaution; he was not sick, Lyon said.

The ten are considered "extremely low-risk" and have restrictions but may leave their homes, he said.

Health officials will not say what counties the ten people are living in or are visiting.

But Lyon said that should not be a concern. None of the individuals are believed to have had any direct contact with the virus; the first of the 21-day monitoring periods will expire early November.

And if Ebola develops, he said, residents will know in which counties the virus was detected.

"There's no reason for anybody to be concerned about these people," he said, noting that in the most Ebola-stricken areas in Africa, victims have been so stigmatized they are reluctant to seek care.

The ten came from different countries and most are not related or know each other, Lyon said.

Each had answered "no" to a variety of questions about whether they had contact with a sick person, visited an area with sick people, or had touched a dead body.

The health department had reported eight people were being monitored in recent days, but the CDC alerted the state of two others earlier today, said state health spokeswoman Jennifer Smith.

She called it a "fluid situation," with individuals being added and others being dropped from monitoring.

Symptoms of Ebola include fever, severe headache, muscle pain, weakness, diarrhea, vomiting, abdominal pain and unexplained bleeding or bruising, according to the CDC, which notes that "symptoms may appear anywhere from two to 21 days after exposure to Ebola, but the average is eight to 10 days."

Meanwhile, local public health officials said they have been in constant contact with the CDC, state health officials, and local health providers and emergency response officials.

Health officials in Wayne, Oakland and Macomb counties echoed Lyon's reassurance to the public about the ten people being monitored:

"There is no reason to panic," said Dr. Mouhanad Hammami, Wayne County health officer.

Earlier this week, Wayne County health officials hosted a meeting attended by about 50 representatives from eight local health departments, health systems and emergency preparedness planners. It was a continuing effort to keep emergency responders and others updated on shifting CDC guidelines, Hammami said.

Though it might seem like a lot of work to keep up with CDC's shifting guidelines for local health officials, it's "reassuring" that they are acting on the most current information to put in place measures to contain any outbreak, said Bill Ridella, health officer for Macomb County.

If Michigan residents are overseas and have contact with sickened Ebola patients, then "there will be some elevated concern," said George Miller, director of the Oakland Health and Human Services department.